THE BIG INDOOR AIR EMISSIONS THREAT – SECONDARY EMISSIONS

Substantial progress has been made understanding volatile organic chemical (VOC) emissions from indoor sources including building materials, furnishing, and some cleaning and maintenance products. During the past two decades, emissions from building materials and other sources have declined significantly in many developed countries. Researchers have begun to understand the potentially larger health threat posed by secondary emission, the chemicals formed by the interactions between oxidants in indoor air and chemicals on surfaces, and by hydrolysis. Many of the by-products of these interactions are more irritating, odorous, or toxic and may pose a far greater health hazard than the chemicals from which they are formed. Building materials, cleaning products, and many consumer products contain chemicals that react with oxidants to form formaldehyde and other, higher molecular weight aldehydes, acidic aerosols, and fine or ultrafine particles. Researchers have identified some of the most important indoor sources that combine with ozone (O3) at common indoor concentrations to form these secondary products. The fundamental processes and critical building material and cleaning products have been identified along with recommendations for minimizing occupant exposure to hazardous chemicals resulting from indoor air chemistry and secondary emissions. Exposure to harmful secondary emissions can be reduced to improve indoor air quality